Model making apparatus



` a Dec. 4, 1951 E L K|BLER 2,577,250

MODEL MAKING APPARATUS Filed June 2K9, 1950 Patented Dec. 4, 1951 UNITED VSTATES PATENT OFFICE l 2,577,250Y i MODEL MAKING APPARATUS Everett L. Kibler, Pittsburgh, Pa. Applieationsun 29, 195o, serial No. 171,050

This invention relates'to a tool Vor apparatus for use in Yproducing an accurate positive cast of a small negative mold of irregular shape, and more particularly Yfor use in dentistry in making casts or models from dental impressions.

As is known in the dentistry art, in order to make a denture and for other purposes,` an impression is rst made of apart of a patients mouth. The impression is obtained through the use of a small tray or cup of suitable shape and material. The impression tray conventionally comprises a small container with a generally U- shapcd trough or rim that receives the modeling plastic or compound, and a short outward eX- tension or handle by which the tray canl be conveniently carried. The .impression is made in the modeling plastic carried by the tray;v and later a cast or model is made from. the impression by pouring or lling the impression lwith the selected casting material and letting Vit harden. The casting material is usually a. gypsum compound, artificial stone, or the like, in the form of a thick, wet mixture or mass.V However, since the contour-surface of a dental impression is irregular, containing ymany small hills and fine pits, itis diicult to ll the impression completely with the casting material in intimate contact with all points of the surface of the impression. This is too Vfrequently prevented by the formation of air bubbles. between the impression and casting material.

A broad object of my inventionis to `provide a simple, inexpensive, long-lived, manually handleable casting devicefor making small casts` or models.

An overall object of my invention is `to provide a'fdevice which can receive different molds, impressions, or matrices for producing casts by hand, the device being readily manipulatable by hand to cause the casting material to follow accurately the surface-contour of the negative-` faithfully iilling allpits and other holes, and cov ering all hills and other rises.

A further object of my invention is to provide a Vmanually operable dental castingv device for making casts or models.

.Another object of my invention is toprovide a dental casting device for use in making casts or models from a dental impression contained` in an impression tray, which device can fbe used over and over again, with the same or dilerent forms of trays.

An important object of my ,inventiongis to provide a dental casting device by means of which accurate dental castor-'stonecanbe produced lil f and more easily and quickly than can be produced by other devices known to the art.

Still another object of my invention is to provide a dental casting device of the type described which can receive any one of an unlimited variety of impression trays having impressions therein from which casts are to be made, the device permitting each tray to be arranged or leveled thereon in any desired manner.

A further object of my invention is to provide a manually operable casting device of the type described, which can be brought against a table corner or other object for the purpose or" jarring or distributing the casting or molding material in the vmatrix carried by the device.

In a preferred form of my invention, the casting device comprises a Yat one-piece base and a handle of suiiicient length to be held in an operators hand. The base is preferablymade of a soft or medium soft Wood. The top of thefcast ing device comprises a generally fiat expanse of waxrwhich is fairly hard but very slightly tacky at` normal room temperatures. The impression tray is carried on the surface of the wax through a plurality of small spaced wax piers that are replaceably secured to the top supporting wax, either by pressureor by a Bunsen burner or other sourcefof heat. The heights of the piers can be readily adjusted so that the impression tray can be arranged in any desired manner with respect to the top wax. After the impression tray is attached to the Wax piers, a ribbon of wax can be used to rbox-in the impression-portion of the tray to form a mold, and the casting material applied to the impression. The casting device can be tapped against' a tablek or other object to force the casting material fully to cover the surface of the impression so that the ultimate cast or model will be an accurate reproduction of the surface and so that air bubbles will be released to pass `from the fluid casting material.

Objects, features and innovations of my invention, in addition to the foregoing, will be discernible from, the following description of a preferred form thereof. The description is to be taken in conjunction with the accompanying drawing, in which:

Fig. 1 is an elevational View, apart thereof being broken away and shown in section, of a castingdevice embodying my invention, the device being shown without a work-holding (impression) tray, the wax supporting piers, and

' othervparts;

Fig. 2 isa plan viewY of the device of Fig. 1;

Fig. 3 is a perspective view, with a part broken away, illustrating the device in use.

The preferred form of my novel casting device is indicated in its entirety in the drawing by the reference numeral 2. As shown in Fig. 2, it has a contour somewhat similar to that of a tabletennis paddle with a flattened end. The casting device 2 comprises a paddle having a wide enlarged portion 4 at one end, and a narrow handle or gripping portion 6 at the other end. In the form of the paddle herein shown, an intermediate portion 8 is between the two end portions. It is to be understood, however, that these portions are not distinct, but merge into each other; and

that the paddle can be shaped differently fromV the form shown in the drawing. However, the shape shown in the drawing is preferred for making casts from dental impressions.

The casting device or paddle comprises a base III having a fiat bottom and a rounded bottom edge I2. The top surface I4 of the base is also at. A fairly stili strip I6 is fastened along the upper part of the outer side of the base l0, extending completely around the base in full contact with the base-side. The strip protrudes above the base-surface I4 to provide upper side walls or a well that is filled with a Wax i8, the wax having a significant depth, the surface of I8 being parallel to the surface I4.

Although other materials can be used, in a form of the device that I have found satisfactory for dental use, the base I6 was a soft wood inch thick, the strip I6 was a brass binding strip, and wax I8 was slightly tacky, such as that known as micro-crystalline Wax, that is, fairly hard at room temperatures, but can be softened readily by a small portable Bunsen burner at spots subjected to the heat of the burner. The metal strip I6 Was tacked to the base I byv pin-tacks, indicated at 2G in the drawing. The strip extended above the base about 15-5 inch, and the resulting well was completely filled up to the level of the top of the strip with Wax I3. This specific form of my invention had a maximum length of just under seven inches, the handle being approximately three and one-half inches. The maximum width was just under five inches. However, it is to be distinctly understood that my invention, in its broader aspects, is not limited to these details.

The supporting top wax I8 serves as a support and mounting medium for an impression tray 22 having gum or other impression 24 thereon. The tray and impression are supported on the .vax I8 through a plurality of small spaced wax pellets or piers, also formed of a tacky micro-crystalline wax. The surfaces of the wax I8 and the attaching pellets or piers being both tacky, the pellets will adhere tightly to the wax I8 with the application of slight pressure thereto. The metal surfaces of the tray 22 can then be adhered to the pellets by pressing it thereagainst, and the tray 22 will then be secured rigidly to the device 2 through the medium of the wax I8. The number, heights and spacings of the wax piers are subject to choice and can depend on the shape of the particular tray to be attached thereto. Thus, the tray 22 has a metal body portion 26 and a short metal handle 28. A wax pier 36 is provided at the end of the handle 28, a pier 32 near the junction of the handle and body portion 26, and a pair of spaced piers 34 at the opposite ends of the body portion. These piers are tacky and can be pressed into intimate attachment to the'wax I8; or a source of concentrated heat, such as a 4 Bunsen burner or hot iron, can be used to melt or soften the bottoms of the Wax piers so that they become integrally united to the face of the supporting wax i8. The tops of the Wax piers can also be softened with heat or pressure shaped so that the tray 22 and impression 24 can be gently adjusted to the desired position with respect to the face of the wax I8. It is to be noted that the tray 22 is carried on the part of the paddle 2 that includesr the enlarged portion 4 and the intermediate portion 8; hence these portions constitute the work-carrying part of the device.

With the impression-carrying tray adjusted to the desired position, it is boxed-in by a ribbon or strip 36 of wax that extends completely around the exposed outside of the tray 22 and impression IIL Cil

24. The strip 36 has sufficient Width to extend from the surface of the supporting Wax I8 to a desired extent above the tray and impression, so as to form a dam for gypsum, or other casting or molding medium that is poured or placed over the impression, preferably as subsequently described. Hence the strip 36 defines the sides of a mold. The strip 36 and the various piers can have a consistency similar to that of the wax I8, being tacky and rm at room temperatures. The strip 36 is sealed by pressure or heat, against the exposed sides of the tray,the impression and the adjacent piers, Vas indicated in Fig. 3. The bottom edge of the strip 36 is also similarly sealed to the face of the supporting wax I8, so that it helps materially to support the impression-carrying tray and to hold it in place when the casting device or paddle is manipulated during the casting process. In effect, the Wax I 6, the piers 30, 32 and 34, and the strip 3,6 form a solid unitary support for the tray, the support being temporarily integrally tied to it so that all of the parts move as a unit to follow the manipulation of the device by an operator moving the handle portion 6 of the paddle, which is long enough to be firmly grasped in the st of the operator.

Assuming that the impression-carrying tray is properly set on the piers and the parts sealed and united, the equipment is ready for the casting operation. The handle 6 may be grasped in one hand and a small amount of casting material poured or placed in any desired portion of the mold formed by the impression 24 and the upper part of the, strip 36. The wax I8 in the handle 6 and the rounded edge I2 at the handle helps the operator to grasp the device more firmly. The operator can now strike the bottom or side of the casting device against a work bench or other suitable structure so as to jolt or rap the equipment. The introduced casting material is caused to ow to all parts of Ythe impression and entrapped air is caused to leave the casting material. The foregoing is repeated until the impression-mold is i-llled to the desired height. The casting material can then be permitted to harden.

Because of the shape and construction of the device an operator can cause the introduced casting material to flow in any or all directions in the impression-mold. An added advantage is the fact that free water or other liquid that isv sometimes present in a casting mixture, can be caused to now from the impression-mold simply by tilting the device slightly.

Because of the ease with which the device can be handled and transported, the casting material can be permitted to lharden in any convenient place. Thus, for example, it may be desirable to permit the cast to harden under Water at a substantially constant temperature, instead of in the open air.

It is evident that the wax strip, the impressioncarrying tray and the piers are readily separable from each other and from the supporting surface wax I8, so that the paddle can receive another impression-carrying tray. The latter can be quite different from the first, but is secured to the wax I8 in the same general manner as already de scribed. Accordingly, the paddle is utilizable with any suitable mold and can be used over and over again with the same or different molds.

Should the surface of the supporting wax I 8 become too rough and dirty, it can be scraped clean and a Bunsen burner or the equivalent passed over its surface to soften or melt the exposed portion so that it can be smoothed out or it can be made to flow smooth. At this time additional wax can be added, if necessary. Because the surface will be frequently subjected to a, ame, it is preferred to make the boundary of the upper surface of the paddle flame-proof, and hence the strip I6 is preferably metal, such as copper. It is also desirable that the device be light in weight so as to avoid a hammer effect When the device is moved against an object in order to jar or vibrate the liquid casting material poured therein. As a rule, light striking blows should be used; and I have found that the -use of Wood for the base 2 seems to give better results than other materials.

In its use as a tool facilitating the fabrication of casts or molds, the casting device of this invention may beused advantageously as a mount to hold the matrix, impression, or mold while employing a mechanical vibrator. In such case, it is merely necessary to hold the device against the vibrator to subject the material being cast to the vibrating action. The casting device of this invention also will be found useful while filling casting rings with investment material in preparing a wax pattern to be cast in metal. In this case, the empty metal casting ring is placed on the surface I8 and sealed thereto by pressure or the use of additional waX to provide a container in which the investment material may be poured. It will also be found useful in the repair of fractured dentures which may be mounted on the wax I8 in position for pouring a mold for effecting the repair. These and other uses of the device will be apparent to those skilled in the dental art.

While I have described my invention in connection with a preferred form, it is obvious that this form is subject to wide modification, and that the principles of my invention can find expression in other embodiments.

I claim:

1. A casting device of the type described comf 2. A casting device as defined in claim 1 but characterized by said base being provided with a handle.

3. A casting device of the type described comprising a wooden base, and a wax top on said base, the opposite faces of said base and said wax being substantially parallel.

4. A casting device of the type described comprising a Wooden base, a wax top on said base, and a handle, the bottom surface of said base and the top surface of said wax being substantially parallel.

5. A casting device as defined in claim 4 characterized by pier means attached to said wax top for supporting a mold.

6. A casting device as defined in claim 4 characterized by a wax ribbon edgewise attached to said wax top, and defining a molding space.

'7. A manually manipulatable casting device comprising a paddle comprising a work-supporting portion having a base, a micro-crystalline wax top, and a handle extending outwardly from said work-supporting portion, said handle having a length so that it can be firmly grasped in the fist of an operator.

8. A casting device as dened in claim 7 but characterized by said base being wood.

9. A manually manipulatable dental casting device comprising a paddle having a wood base prising a work-carrying portion having a base,

a shallow well portion above said base, and a wax filling said well portion and comprising the top for said device.

having an enlarged work-supporting portion and an outwardly extending handle portion, a strip attached to the side of said base and forming a well therewith over the face of said base, and wax filling said well and forming an exposed wax top portion for said paddle.

10. A casting device as defined in claim 9 characterized by opposite exposed surfaces of said base and said wax top portion being substantially parallel over substantially the full length of said paddle.

11. A casting device of the type described comprising a flat paddle having a work-supporting portion and a handle extending outwardly from said Work-supporting portion, said Work-supporting portion having a shallow well on one surface thereof, and a wax tacky at room temperature filling said well, the depth of said well being substantially uniform throughout.

EVERETT L. KIBLER.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,382,010 Nishi June 21, 1921 1,470,826 Gambill Oct. 16, 1923 1,834,980 Stealy Dec. 8, 1931' 

